Tour: Super Flares

The long relationships between stars and the planets around them — including the Sun and the Earth — may be even more complex than previously thought. This is one of the conclusions from a new study involving thousands of stars using NASA's Chandra X-ray Observatory.

By conducting the largest survey ever of star-forming regions in X-rays, a team of researchers has helped outline the link between very powerful flares, or outbursts, from youthful stars, and the impact they could have on planets in orbit.

This work tells astronomers how the Sun may have acted and potentially affected the young Earth billions of years ago. The scientists examined Chandra's X-ray data of more than 24,000 stars in 40 different regions where stars are forming. Today, our Sun is constantly active, giving off flares of different sizes and intensities depending on where it is in its 11-year solar cycle. Sometimes a particularly powerful solar storm will directly impact Earth by knocking out communications satellites or disrupting electrical grids. Most of these, however, pale in comparison to the strongest solar storm on record, which became known as the "Solar Carrington Event" in 1859.

The powerful flares in the young stars in this new Chandra study are much, much bigger than Carrington. The researchers found that each young star, on average, experienced a "super" flare — one that is at least 100,000 times more energetic than the Carrington Event — about once per week. They also discovered that these stars had a "mega" flare — up to 10 million times greater than Carrington — a couple of times per year on average. The scientists detected these giant flares in all of the star-forming regions they observed and in young stars of all different masses, including those similar to the Sun.

By learning more about the frequency of these extremely powerful flares, scientists can better understand the impacts they may have on the planets forming around them. For example, the flares could benefit a developing planet by driving gas away from disks of material that surround them. This can trigger the formation of pebbles and other small rocky material that is a crucial step for planets to form. On the other hand, powerful flares could destroy an atmosphere of a planet, removing its protective shield from damaging radiation.

Scientists will continue to use Chandra to study these flares to find out what kinds of impact — both good and bad — these flares have on the early lives of planets.

This new high-energy tapestry is a reminder how complex and compelling our Galaxy is.